Beds used in hospitals, other health care facilities and home health care settings include a deck and a mattress supported by the deck. Some beds have a fixed width deck. Other beds include a fixed width center deck section, a left width adjustment wing and a right width adjustment wing. The wings can be stored under the fixed width center section, in which case the deck width equals the width of the fixed width section. The wings can also be stored partially under the fixed width center section so that they each project laterally beyond the lateral edges of the center section by a distance D1, in which case the deck width equals the width of the fixed width section plus two times the distance D1. The wings can also be deployed so that they each project laterally beyond the lateral edges of the fixed width section by a distance D2, which is greater than D1, in which case the deck width equals the width of the fixed width section plus two times the distance D2. With the wings deployed, the bed may be outfitted with a bariatric mattress, which is wider than a nonbariatric mattress, to accommodate a bariatric occupant. A typical bariatric mattress has a center section, a left width augmentation section and a right width augmentation section. Examples of augmentation sections include air filled bladders and foam inserts. The width adjustment wings are useful because with the wings deployed in order to accommodate a bariatric occupant the bed is too wide to fit through a typical doorway. When it becomes necessary to transport the occupant to a different location without removing him or her from the bed, the wings can be temporarily moved to their stored position and the mattress can be temporarily reduced in width, for example by deflating the augmentation bladders or laterally compressing the augmentation foam, so that the bed is able to fit through the doorways. Upon reaching the intended destination the bed can then be restored to its bariatric configuration, i.e. with the wings deployed and the mattress re-expanded to its bariatric width.
In a typical width adjustable bed the stored position of the wings is underneath the fixed width deck section. A caregiver deploys the wings by manually pulling them laterally away from the longitudinal centerline of the bed, and stores them by manually pushing them laterally toward the centerline. U.S. Pat. No. 7,730,562 describes a bed having powered width expansion wings. The only specific means disclosed for powering the wings are a hydraulic cylinder or a linear actuator. Such actuation devices can suffer from disadvantages such as bulk, weight and cost. Accordingly, it is desirable to devise more compact, lightweight, low cost systems for powering the expansion wings without sacrificing simplicity and reliability. It is also desirable if such systems can be retrofit onto existing beds having manually operated wings. It is also desirable if such systems or their components can be economically and easily repaired or replaced when necessary.